Ireland’s solar output hits 1,258 MW before eclipse

Just before 1 p.m. on Tuesday, 11 August, Ireland’s electricity grid saw solar generation climb to 1,258 MW. It was the highest grid-scale solar peak recorded in the country, with solar supplying around a third of all electricity used nationally at that moment.

The record came after July became Ireland’s strongest month yet for solar energy, according to EirGrid, the country’s transmission system operator. Ireland now has over 8 GW of renewable electricity generation capacity connected to its network, up from just 2 MW of solar just over 10 years ago. Solar deployment has since passed 2.6 GW, although most renewable generation still comes from wind.

The next day, the eclipse coincided with a sharp drop in grid-scale solar generation. At 6.15 p.m. on 12 August, during the eclipse, grid-scale solar was generating 532 MW. That fell to 202 MW by 6.45 p.m. and then to 8 MW at the eclipse’s height 30 minutes later. As the Moon moved away, output recovered gradually, reaching 51 MW by 7.30 p.m. and 83 MW at 7.45 p.m.

The eclipse’s effect was visible in Ireland’s generation curve, a detail that Ronan Power, CEO of Solar Ireland, said turned the event into a chance for people to track output from their rooftop systems on their phones. Europe’s transmission system operators had forecast a temporary reduction in solar generation, but said they were not concerned about overall electricity supply. In Ireland, EirGrid recorded a peak of 1,090 MW at 1.45 p.m., ahead of a forecast peak of 1,038 MW.

So what does this change in practice? For Ireland, solar is no longer a marginal source that appears only in project plans: its output can now cover around a third of national electricity use at a peak and its fluctuations are visible in the national grid data. The eclipse coincided with a temporary fall in output, followed by a gradual recovery. The episode made changes in solar generation visible in Ireland’s national generation data.